This shuttle image shows a winter view of the Mistastin Crater, a heavily
eroded complex structure. Eastward moving glaciers have drastically
reduced the surface expression of this structure, removing most of the
impact melt sheet and breccias and exposing the crater floor. Glacial
erosion has also imparted an eastward elongation to the crater that is
particularly evident in the shape of the lake that occupies the central
10 kilometers (6 miles)
of the structure. Horseshoe Island, in the center of the lake, is
part of the central uplift and contains shocked Precambrian crystalline
target rocks. Just beyond the margins of the lake are vestiges of the
impact melt sheet that contains evidence of meteoritic features in
quartz, feldspar and diaplectic glasses.